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Nuclear fusion milestone passed at US lab

bbc.co.uk

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Re: Nuclear fusion milestone passed at US lab

#161

Post by rdl »

andygates wrote: post #153
pdonis wrote: post #123

Earlier quoted context omitted.

It wasn't "the Japanese" that didn't do it safely at Fukushima. It was GE Was GE responsible for the siting of the backup diesel generators and switchgear behind a seawall that was overcome by the tsunami? That was the root cause of all the problems; it wasn't anything to do with the reactor design itself, other than the fact that it needed active cooling after shutdown (which PWR designs from the same time period al…

But the backup generators could be moved (and were in similar US installations). Raising the backup generators to protect them against inundation was recommended, but the delay there is pure sclerotic TEPCO.

I still don't understand why Chinooks weren't in the air toward Fukushima within 30 minutes of the tsunami with some generators sling-loaded under them (and refueling, etc.). Either from the JSDF or US Military.

Re: Nuclear fusion milestone passed at US lab

#162

Post by Robin_Message »

crystaln wrote: post #137
mquander wrote: post #94

Earlier quoted context omitted.

Coal power creates that kind of crisis every day, so we don't bother calling it a crisis anymore. A total of 240,000 years of life were said to be lost in Europe in 2010 with 480,000 work days a year and 22,600 "life years" lost in Britain, the fifth most coal-polluted country. http://www.theguardian.com/environment/2013/jun/12/european-...

"commissioned by Greenpeace International" who I'm sure would back the position that nuclear fission plants are safer than coal. Of course, nuclear power plants are safe short term. Their threat is catastrophe, which given time, is inevitable.

Because of Greenpeace's history (the death of an anti-nuclear testing activist and the destruction of one of their ships at the hands of French special forces in 1985 [1]), and their current anti-nuclear stance [2], I don't think they would back that position.

They would back the position that wind turbines are safer than coal, so you're not wrong that they might be biased to imply coal is more dangerous than it is.

[1] http://en.wikipedia.org/wiki/Sinking_of_the_Rainbow_Warrior

[2] http://www.greenpeace.org/international/en/campaigns/nuclear...

Re: Nuclear fusion milestone passed at US lab

#163

Post by tezza »

XorNot wrote: post #152
drjesusphd wrote: post #133

Earlier quoted context omitted.

> What I am saying, is that relative to other potential investments, fusion does not seem to be a worthwhile investment, as the risk/payoff ratio is worse. I disagree. There exists MILLIONS of years worth of fuel on earth, compared to a few decades of oil and gas, and a few hundred years worth old coal or fissionable uranium. That's quite a huge payoff for relatively little risk (compare fusion research funding with…

The ITER project's lifetime cost is currently less then the California rail system or a British rail extension. When people start talking about cost, let's put those numbers in perspective. The AIG bailout alone would've bought 6-7 ITERs.

> AIG bailout alone would've bought 6-7 ITERs.

I agree with your other points. But the AIG bailout not only saved filthy rich bankers, but saved the entire world economy.

Private pensions would have been wiped out, who own 95% of the stockmarket. The pensions were chasing gains and were quite happy while the returns were fat. The government cannot afford its own pension promises anyway and would have been wiped out.

Big science projects are paid in installments over many years. If the financial system collapses, for sure the big projects will be mothballed immediately.

Re: Nuclear fusion milestone passed at US lab

#164

Post by JonnieCache »

tsenkov wrote: post #140
sam wrote: post #47

It is an important milestone. But to have a commercially viable fusion reactor, you'll need a factor of 50-100 more energy out than in to make up for inefficiencies in electricity generation using this kind of scheme. The real story here is that this facility allows the US to do nuclear weapons research without violating the nuclear test ban treaty. If the goal was to develop a commercially viable fusion reactor, the…

I wonder, what more do they need in nuclear weapons? Smaller size? Harder detection? Bigger contamination radius? Somehow, I am sure, if people start a nuclear war, even the WWII's initial nuclear weaponry will be enough to destroy ourselves, knowing how many countries can now chime in with their own.

The US now has a notion of "tactical" nuclear weapons.

Some reading:

http://www.fas.org/_docs/Non_Strategic_Nuclear_Weapons.pdf

God help us all.

Re: Nuclear fusion milestone passed at US lab

#165

Post by _b8r0 »

ballard wrote: post #138
drjesusphd wrote: post #136

Earlier quoted context omitted.

They did not mention Q at all in the article and their claims cannot be compared to any intellectually honest definition of "break even" in good faith without more information

IIRC from a recent HN discussion, ITER has attained Q of 0.65 and NIF is nowhere close to that.

Are you sure you're not thinking of JET[1]? ITER's not scheduled to be operational until 2020 AFAICR.

Incidentally when I went to see JET (it's up the road from me, not that far from Oxford) the scale of the thing was enormous. They mentioned that they'd had been able to sustain plasma for 600 seconds. I've got some pictures up[2] on flickr.

[1] - http://www.i15.p.lodz.pl/strony/EIC/ne/future_2_1.html

[2] - http://www.flickr.com/photos/z3r0kl3w/sets/72157623979315835...

Re: Nuclear fusion milestone passed at US lab

#166

Post by ewoodrich »

JonnieCache wrote: post #164
tsenkov wrote: post #140

Earlier quoted context omitted.

I wonder, what more do they need in nuclear weapons? Smaller size? Harder detection? Bigger contamination radius? Somehow, I am sure, if people start a nuclear war, even the WWII's initial nuclear weaponry will be enough to destroy ourselves, knowing how many countries can now chime in with their own.

The US now has a notion of "tactical" nuclear weapons. Some reading: http://www.fas.org/_docs/Non_Strategic_Nuclear_Weapons.pdf God help us all.

That's been around since 1953 (less than a decade after the first atomic detonation in '45). [1]

And we've maintained a limited number of low-yield warheads that would fall under that designation. [2] (as an example)

[1] http://en.wikipedia.org/wiki/Nuclear_artillery

[2] http://en.wikipedia.org/wiki/B61_nuclear_bomb

Re: Nuclear fusion milestone passed at US lab

#167

Post by XorNot »

tezza wrote: post #163
XorNot wrote: post #152

Earlier quoted context omitted.

The ITER project's lifetime cost is currently less then the California rail system or a British rail extension. When people start talking about cost, let's put those numbers in perspective. The AIG bailout alone would've bought 6-7 ITERs.

> AIG bailout alone would've bought 6-7 ITERs. I agree with your other points. But the AIG bailout not only saved filthy rich bankers, but saved the entire world economy. Private pensions would have been wiped out, who own 95% of the stockmarket. The pensions were chasing gains and were quite happy while the returns were fat. The government cannot afford its own pension promises anyway and would have been wiped out.…

The point is that governments have this type of money. In spades. Pretending we're not properly prioritizing one type of research or another is a farce - if you can convince anyone to invest in nuclear fission reactors, whether they do that won't really be affected by how much fusion research is happening. That's not why we don't have nuclear fission right now, but shutting down nuclear fusion might just ensure we never get either.

Re: Nuclear fusion milestone passed at US lab

#168

Post by VLM »

stormbrew wrote: post #121
acadien wrote: post #101

Earlier quoted context omitted.

I thought the goal was to have a self sustaining reaction that would only require laser pulses to hold it in place. Is a continuously pulsed laser necessary to provide thermal energy to drive the reaction? Also I've read (sorry no citation) that the indirect drive was necessary to ensure even dispersal of the heat generated by the initiating laser blast. Any clarification would be much appreciated, this isn't my fiel…

My layman's understanding of the subject is that you want (and get) anything but a self-sustaining reaction with fusion, and that's actually one of its safety features compared to fission (where a chain reaction is allowed to happen in a controlled way -- if something goes wrong the reaction keeps going, out of control). You do want to use the energy from one reaction to power the next, but not directly. No one's act…

"one of its safety features compared to fission"

Not exactly. Off the top of my head I can't think of a reactor thats unstable in operation. Hands off (like that TV series life after humans where the people all disappear) almost all stabilize and eventually shutdown on their own. Maybe those crazy graphite reactors are not inherently stable.

There's two linked issues.

Fission reactors get about 10% of their heat from decay products (the "waste") decaying away. That means there is no instant off switch. The "off" position is still 10% out for hours/days/weeks (well it decays away eventually...). As the Japanese found out the hard way, 10% of a huge amount of power is enough residual heat to cause an awful disaster.

The other is surface area / volume ratio. Couple gigawatts thermal like the Japanese and there's not enough surface area to cool it without giant pumps when shutdown. Couple MW like a nuclear sub and the surface area ratio is better, theoretically you could probably walk away from one without anything awful happening. The people who know aren't talking. Fusion you're talking about something a millimeter across not multiple meters. Walk away or have a computer crash or whatever and it seems impossible for something that small to cause much damage.

There are some practical physics reasons why making a fusion reactor the size of the sun is really easy and the smaller you go the harder it gets, but there are practical engineering reasons why making one bigger than a millimeter would be a huge PITA. On the other hand if you could make a fission reactor the size of a millimeter that would certainly solve a lot of painful thermal engineering problems, but the physics just doesn't work (long story...)

Re: Nuclear fusion milestone passed at US lab

#169

Post by njharman »

pjlegato wrote: post #67
sam wrote: post #47

It is an important milestone. But to have a commercially viable fusion reactor, you'll need a factor of 50-100 more energy out than in to make up for inefficiencies in electricity generation using this kind of scheme. The real story here is that this facility allows the US to do nuclear weapons research without violating the nuclear test ban treaty. If the goal was to develop a commercially viable fusion reactor, the…

Speculating about their "real" motives is just that; speculation. I'm sorry your project was defunded, but that in itself is not evidence that the facility is actually a sham.

You say "speculation" as if it were a bad thing.

Re: Nuclear fusion milestone passed at US lab

#170

Post by VLM »

tsenkov wrote: post #140
sam wrote: post #47

It is an important milestone. But to have a commercially viable fusion reactor, you'll need a factor of 50-100 more energy out than in to make up for inefficiencies in electricity generation using this kind of scheme. The real story here is that this facility allows the US to do nuclear weapons research without violating the nuclear test ban treaty. If the goal was to develop a commercially viable fusion reactor, the…

I wonder, what more do they need in nuclear weapons? Smaller size? Harder detection? Bigger contamination radius? Somehow, I am sure, if people start a nuclear war, even the WWII's initial nuclear weaponry will be enough to destroy ourselves, knowing how many countries can now chime in with their own.

Its the ongoing expense. Look over time, what does it cost to maintain the ability to use one?

Inflation adjusted cost of the entire B-52 program including all maintenance and crew personnel and their training? I donno, like a billion?

A missile field is cheaper to maintain (I think?) and not much more to develop, so its probably a bit under a billion.

A nuke launching sub might cost a billion but it holds alot of them so divided out is probably only hundreds of millions

Grats you've now got one so small and light a plain old fighter-bomber plane only 10 million or so can drop one.

Finally small and cheap enough to do some million dollar class cruise missiles.

I'm sure we'll eventually have cheap drones as delivery vehicles.

The point is minimizing spent money during peacetime. A bunker full of cruise missiles is infinitely cheaper than multiple operating wings of B-52.

The other (obvious?) idea is burying history. Say Canada wanted to nuke us for invading and regime changing them to steal their maple syrup. It could happen. IF we used 1940s techniques which only require a billion or so and a couple months or a whole year, anything their spies steal is very dangerous. On the other hand, "Go ahead, steal these 1980s kryton switch designs, it'll take you 50 years and a trillion bucks to figure out how to use them not to mention all the extra stuff that goes with those handy dandy trigger mechanisms". A good analogy is the time machine. So you can visit Bavaria in the 1300s if you sneak a 1500s level wooden clock escapement that would probably revolutionize Bavaria in the 1300s one way or the other. On the other hand sneak in a modern AMD64 CPU, just the bare chip, not even a heatsink or a PCB or anything, just the chip, and they're going to be all "WTF" all they have to do is get to the 2000s or so, and this will chip will leapfrog them into the 2010s, but its going to take a heck of a long time to get them from 1300s to 2000s without any help. So, yeah, go steal that modern US design, a mere couple trillion bucks and 70 years experience and you'll be stamping them out like license plates just like us. I guess by the 2080s we should be worried, but right now no problemo.

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